Emitter array with multiple groups of interspersed emitters

ABSTRACT

An optical device may include an emitter array including a plurality of emitter groups. Each emitter group may be independently addressable from other emitter groups, of the plurality of emitter groups, for independently lasing. Emitters of the plurality of emitter groups may be interspersed within the emitter array such that a minimum emitter-to-emitter distance within the emitter array is less than a minimum emitter-to-emitter distance within any of the emitter groups.

RELATED APPLICATION

This application claims priority to U.S. Provisional Patent ApplicationNo. 62/745,029, filed on Oct. 12, 2018, the content of which isincorporated by reference herein in its entirety.

TECHNICAL FIELD

The present disclosure relates to an emitter array and, moreparticularly, to an emitter array with multiple groups of interspersedemitters.

BACKGROUND

An emitter can include a vertical-emitting device, such as a verticalcavity surface emitting laser (VCSEL). A VCSEL is a laser in which abeam is emitted in a direction perpendicular to a surface of the VCSEL(e.g., vertically from a surface of the VCSEL). Multiple emitters may bearranged in an emitter array with a common substrate.

SUMMARY

According to some implementations, an optical device may include anemitter array including a plurality of emitter groups, each emittergroup being independently addressable from other emitter groups, of theplurality of emitter groups, for independently lasing, and emitters ofthe plurality of emitter groups being interspersed within the emitterarray such that a minimum emitter-to-emitter distance within the emitterarray is less than a minimum emitter-to-emitter distance within any ofthe emitter groups.

According to some implementations, an optical device may include anemitter array including a first plurality of emitters, a secondplurality of emitters, and a third plurality of emitters, whereinemitters from the first plurality of emitters the second plurality ofemitters, and the third plurality of emitters are interspersed in theemitter array, wherein a first minimum emitter-to-emitter distancebetween any two adjacent emitters of the emitter array is less than asecond minimum emitter-to-emitter distance, the second minimumemitter-to-emitter distance being a minimum emitter-to-emitter distancebetween any two emitters of the first plurality of emitters, or aminimum emitter-to-emitter distance between any two emitters of thesecond plurality of emitters, or a minimum emitter-to-emitter distancebetween any two emitters of the third plurality of emitters, wherein thefirst plurality of emitters, the second plurality of emitters, and thethird plurality of emitters are independently addressable forindependent lasing.

According to some possible implementations, a vertical cavity surfaceemitting laser (VCSEL) array may include at least three groups ofVCSELs, wherein VCSELs of a first group of the at least three groups ofVCSELs are interspersed among VCSELs of a second group of the at leastthree groups of VCSELs, the VCSELs of the second group of VCSELs areinterspersed among VCSELs of a third group of the at least three groupsof VCSELs, and the VCSELs of the third group of the at least threegroups of VCSELs are interspersed among the VCSELs of the first group ofthe at least three groups of VCSELs, wherein a first minimumemitter-to-emitter distance between any two adjacent VCSELs of the atleast three groups of VCSELs of the VCSEL array is less than a secondminimum emitter-to-emitter distance between two VCSELs of any one of theat least three groups of VCSELs, wherein the VCSEL array is configuredsuch that the at least three groups of VCSELs are capable of lasingindependently of each other.

According to some possible implementations, a method may includeproviding a substrate on which a laser array is to be formed; forming,after providing the substrate, first lasers of the laser array, secondlasers of the laser array, and third lasers of the laser array on orwithin the substrate such that: the first lasers are interspersed amongthe second lasers, the second lasers are interspersed among the thirdlasers, and the third lasers are interspersed among the first lasers, afirst minimum emitter-to-emitter distance between any two adjacentlasers of the laser array is less than a corresponding second minimumemitter-to-emitter distance between two of the first lasers, two of thesecond lasers, or two of the third lasers, and the first lasers, thesecond lasers, and the third lasers are electrically isolated from eachother for independent lasing; and electrically connecting the firstlasers, the second lasers, and the third lasers to correspondingelectrodes.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B are diagrams depicting a top-view of an examplevertical-emitting device and a cross-sectional view of the examplevertical-emitting device, respectively.

FIGS. 2A-4 are diagrams depicting one or more example implementationsdescribed herein.

FIG. 5 is a flow chart of an example process for forming an emitterarray with multiple groups of interspersed emitters.

FIG. 6 is a diagram of an example illustrating principles ofdepth-of-field of an emitter array.

DETAILED DESCRIPTION

The following detailed description of example implementations refers tothe accompanying drawings. The same reference numbers in differentdrawings may identify the same or similar elements.

When emitter arrays are used for structured-light three-dimensional (3D)sensing, a manufacturer may want to pack more emitters onto a singledie. However, for some 3D sensing systems it is necessary to distinguishindividual emitters projected into a scene. The light from the emittersmay be projected through lenses and or other optics and come into focusagain at an image plane. At the image plane, the emitters will appearseparated in proportion to their displacement on the die. However, atdepths closer or further from the image plane (e.g., a z-direction), theprojected size of the emitters will increase and eventually they willmerge into each other. FIG. 6 is a diagram illustrating these principlesof depth-of-field of an emitter array. For the system to function over awide variation in depth, the beam divergence needs to be sufficientlysmall and there needs to be sufficient separation between emitters sothere is a sufficient depth-of-field from the image plane where it ispossible to distinguish individual emitters. As emitters are moreclosely spaced, emission areas of the emitters must be reducedcorrespondingly to avoid overlap of the emission areas too near to theimage plane even though the emission areas may not overlap on the chipitself. Furthermore, with a smaller emission area, variation in adiameter or a size (e.g., an optical aperture) of the emitters needs tobe reduced in order to maintain a fixed percentage error (e.g., lessthan +/−20 percent) in current density and output power of individualemitters (which are typically driven in parallel from a single contact).Reducing a diameter and/or size of emitters of an emitter array resultsin reduced process yield. This tradeoff between emitter size and yieldnormally limits the emitter spacing on the chip. This invention providesa chip design to overcome this limitation.

Some implementations described herein provide an emitter array withmultiple groups of interspersed emitters (e.g., chosen to permit largeremitter sizes with a smaller fabrication spacing and/or a wider range ofdepth of sensing than otherwise possible with a single group of emittersused in a 3D sensing system). For example, some implementationsdescribed herein provide an emitter array with interspersed groups ofemitters arranged so that a minimum emitter-to-emitter (e.g.,center-to-center distance or spacing) between proximate emitters withineach group is substantially larger than a minimum emitter-to-emitterdistance between adjacent emitters of the emitter array.

Specifically, some implementations described herein provide for largeremitters with larger variation in aperture sized in high densityconfigurations and/or provide for sensing over a longer depth of field,as compared to emitters used in conventional high density emitter arraysfor structured light. For example, a conventional emitter array with aminimum emitter-to-emitter distance of 24 microns (μm) may need emitterapertures with a diameter of 7 μm in order to avoid overlap of projectedspots of adjacent emitters near (e.g., 5 centimeters (cm) away from) animage plane. To ensure that optical power and operating current densitydo not vary more than, for example, +/−20 percent, the emitter sizevariation may need to be less than +/−10 percent or +/−0.7 μm. Such asmall permissible emitter size variation may decrease yield.

Some implementations described herein, and with respect to the exampledescribed above, may facilitate use of emitters patterned with a minimumdistance of 24 μm, but with a size greater than 7 μm (for example, 12μm), and a tolerance on the aperture size of +/−1.2 μm (approximately+/−10 percent of the example emitter size) to ensure that the currentdensity and optical power variation is less than +/−20 percent, and sothat emission spots from adjacent emitters do not appreciably overlapwithin a given distance from an image plane. Such a larger permissibleemitter size variation may increase yield. Additionally, oralternatively, some implementations described herein provide for use ofan emitter array with the same minimum distance between emitters (e.g.,but having an intermediate size of, for example, 10 μm) while extendingthe depth of field beyond, for example, 5 cm from the image plane (e.g.,to 8 cm) with respect to overlap of emission spots for adjacentemitters.

FIGS. 1A and 1B are diagrams depicting a top-view of an example emitter100 and a cross-sectional view 150 of example emitter 100 along the lineX-X, respectively. As shown in FIG. 1A, emitter 100 may include a set ofemitter layers constructed in an emitter architecture. In someimplementations, emitter 100 may correspond to one or morevertical-emitting devices described herein.

As shown in FIG. 1A, emitter 100 may include an implant protection layer102 that is circular in shape, in this example. In some implementations,implant protection layer 102 may have another shape, such as anelliptical shape, a polygonal shape, or the like. Implant protectionlayer 102 is defined based on a space between sections of implantmaterial (not shown) included in emitter 100.

As shown by the medium gray and dark gray areas in FIG. 1A, emitter 100includes an ohmic metal layer 104 (e.g., a P-Ohmic metal layer or anN-Ohmic metal layer) that is constructed in a partial ring-shape (e.g.,with an inner radius and an outer radius). The medium gray area shows anarea of ohmic metal layer 104 covered by a protective layer (e.g. adielectric layer, a passivation layer, and/or the like) of emitter 100and the dark gray area shows an area of ohmic metal layer 104 exposed byvia 106, described below. As shown, ohmic metal layer 104 overlaps withimplant protection layer 102. Such a configuration may be used, forexample, in the case of a P-up/top-emitting emitter 100. In the case ofa bottom-emitting emitter 100, the configuration may be adjusted asneeded.

Not shown in FIG. 1A, emitter 100 includes a protective layer in whichvia 106 is formed (e.g., etched). The dark gray area shows an area ofohmic metal layer 104 that is exposed by via 106 (e.g., the shape of thedark gray area may be a result of the shape of via 106) while the mediumgrey area shows an area of ohmic metal layer 104 that is covered by theprotective layer. The protective layer may cover all of the emitterother than the vias. As shown, via 106 is formed in a partial ring-shape(e.g., similar to ohmic metal layer 104) and is formed over ohmic metallayer 104 such that metallization on the protection layer contacts ohmicmetal layer 104. In some implementations, via 106 and/or ohmic metallayer 104 may be formed in another shape, such as a full ring-shape or asplit ring-shape.

As further shown, emitter 100 includes an optical aperture 108 in aportion of emitter 100 within the inner radius of the partial ring-shapeof ohmic metal layer 104. Emitter 100 emits a laser beam via opticalaperture 108. As further shown, emitter 100 also includes a currentconfinement aperture 110 (e.g., an oxide aperture formed by an oxidationlayer of emitter 100 (not shown)). Current confinement aperture 110 isformed below optical aperture 108.

As further shown in FIG. 1A, emitter 100 includes a set of trenches 112(e.g., oxidation trenches) that are spaced (e.g., equally, unequally)around a circumference of implant protection layer 102. How closelytrenches 112 can be positioned relative to the optical aperture 108 isdependent on the application, and is typically limited by implantprotection layer 102, ohmic metal layer 104, via 106, and manufacturingtolerances.

The number and arrangement of layers shown in FIG. 1A are provided as anexample. In practice, emitter 100 may include additional layers, fewerlayers, different layers, or differently arranged layers than thoseshown in FIG. 1A. For example, while emitter 100 includes a set of sixtrenches 112, in practice, other configurations are possible, such as acompact emitter that includes five trenches 112, seven trenches 112,and/or the like. In some implementations, trench 112 may encircleemitter 100 to form a mesa structure d_(t) (see FIG. 1B). As anotherexample, while emitter 100 is a circular emitter design, in practice,other designs may be used, such as a rectangular emitter, a hexagonalemitter, an elliptical emitter, or the like. Additionally, oralternatively, a set of layers (e.g., one or more layers) of emitter 100may perform one or more functions described as being performed byanother set of layers of emitter 100.

Notably, while the design of emitter 100 is described as including aVCSEL, other implementations are possible. For example, the design ofemitter 100 may apply in the context of another type of optical device,such as a light emitting diode (LED), or another type of verticalemitting (e.g., top emitting or bottom emitting) optical device.Additionally, the design of emitter 100 may apply to emitters of anywavelength, power level, emission profile, and/or the like. In otherwords, emitter 100 is not particular to an emitter with a givenperformance characteristic.

The example cross-sectional view shown in FIG. 1B may represent across-section of emitter 100 that passes through, or between, a pair oftrenches 112 (e.g., as shown by the line labeled “X-X” in FIG. 1A). Asshown, emitter 100 may include a backside cathode layer 128, a substratelayer 126, a bottom mirror 124, an active region 122, an oxidation layer120, a top mirror 118, an implant isolation material 116, a protectivelayer 114 (e.g. a dielectric passivation/mirror layer), and an ohmicmetal layer 104. As shown, emitter 100 may have, for example, a totalheight that is approximately 10 μm.

Backside cathode layer 128 may include a layer that makes electricalcontact with substrate layer 126. For example, backside cathode layer128 may include an annealed metallization layer, such as an AuGeNilayer, a PdGeAu layer, or the like.

Substrate layer 126 may include a base substrate layer upon whichepitaxial layers are grown. For example, substrate layer 126 may includea semiconductor layer, such as a GaAs layer, an InP layer, and/or thelike.

Bottom mirror 124 may include a bottom reflector layer of emitter 100.For example, bottom mirror 124 may include a distributed Bragg reflector(DBR). Bottom mirror 124 is shown as the white area beneath activeregion 122 between the left and right portions of isolation material116.

Active region 122 may include a layer that confines electrons anddefines an emission wavelength of emitter 100. For example, activeregion 122 may be a quantum well.

Oxidation layer 120 may include an oxide layer that provides optical andelectrical confinement of emitter 100. In some implementations,oxidation layer 120 may be formed as a result of wet oxidation of anepitaxial layer. For example, oxidation layer 120 may be an Al₂O₃ layerformed as a result of oxidation of an AlAs or AlGaAs layer. Trenches 112may include openings that allow oxygen (e.g., dry oxygen, wet oxygen) toaccess the epitaxial layer from which oxidation layer 120 is formed.

Current confinement aperture 110 may include an optically activeaperture defined by oxidation layer 120. A size of current confinementaperture 110 may range, for example, from approximately 4 μm toapproximately 20 μm. In some implementations, a size of currentconfinement aperture 110 may depend on a distance between trenches 112that surround emitter 100. For example, trenches 112 may be etched toexpose the epitaxial layer from which oxidation layer 120 is formed.Here, before protective layer 114 is formed (e.g., deposited), oxidationof the epitaxial layer may occur for a particular distance (e.g.,identified as d_(o) in FIG. 1B) toward a center of emitter 100, therebyforming oxidation layer 120 and current confinement aperture 110. Insome implementations, current confinement aperture 110 may include anoxide aperture. Additionally, or alternatively, current confinementaperture 110 may include an aperture associated with another type ofcurrent confinement technique, such as an etched mesa, a region withoution implantation, a lithographically defined intra-cavity mesa andregrowth, or the like.

Top mirror 118 may include a top reflector layer of emitter 100. Forexample, top mirror 118 may include a DBR. Top mirror 118 is shown asthe white area above oxidation layer 120 between the left and rightportions of isolation material 116.

Implant isolation material 116 may include a material that provideselectrical isolation. For example, implant isolation material 116 mayinclude an ion implanted material, such as a hydrogen/proton implantedmaterial or a similar implanted element to reduce conductivity. In someimplementations, implant isolation material 116 may define implantprotection layer 102.

Protective layer 114 may include a layer that acts as a protectivepassivation layer and which may act as an additional DBR. For example,protective layer 114 may include one or more sub-layers (e.g., adielectric passivation layer and/or a mirror layer, a SiO₂ layer, aSi₃N₄ layer, an Al₂O₃ layer, or other layers) deposited (e.g., bychemical vapor deposition, atomic layer deposition, or other techniques)on one or more other layers of emitter 100.

As shown, protective layer 114 may include one or more vias 106 thatprovide electrical access to ohmic metal layer 104. For example, via 106may be formed as an etched portion of protective layer 114 or alifted-off section of protective layer 114. Optical aperture 108 mayinclude a portion of protective layer 114 over current confinementaperture 110 through which light may be emitted.

Ohmic metal layer 104 may include a layer that makes electrical contactthrough which electrical current may flow. For example, ohmic metallayer 104 may include a Ti and Au layer, a Ti and Pt layer and/or an Aulayer, or the like, through which electrical current may flow (e.g.,through a bondpad (not shown) that contacts ohmic metal layer 104through via 106). Ohmic metal layer 104 may be P-ohmic, N-ohmic, and/orthe like. Selection of a particular type of ohmic metal layer 104 maydepend on the architecture of the emitters. Ohmic metal layer 104 mayprovide ohmic contact between a metal and a semiconductor and/or mayprovide a non-rectifying electrical junction and/or may provide alow-resistance contact.

In some implementations, emitter 100 may be manufactured using a seriesof steps. For example, bottom mirror 124, active region 122, oxidationlayer 120, and top mirror 118 may be epitaxially grown on substratelayer 126, after which ohmic metal layer 104 may be deposited on topmirror 118. Next, trenches 112 may be etched to expose oxidation layer120 for oxidation. Implant isolation material 116 may be created via ionimplantation, after which protective layer 114 may be deposited. Via 106may be etched in protective layer 114 (e.g., to expose ohmic metal layer104 for contact). Plating, seeding, and etching may be performed, afterwhich substrate layer 126 may be thinned and/or lapped to a targetthickness. Finally, backside cathode layer 128 may be deposited on abottom side of substrate layer 126.

The number, arrangement, thicknesses, order, symmetry, or the like, oflayers shown in FIG. 1B is provided as an example. In practice, emitter100 may include additional layers, fewer layers, different layers,differently constructed layers, or differently arranged layers thanthose shown in FIG. 1B. Additionally, or alternatively, a set of layers(e.g., one or more layers) of emitter 100 may perform one or morefunctions described as being performed by another set of layers ofemitter 100 and any layer may comprise more than one layer.

FIGS. 2A-2D are diagrams depicting one or more example implementations200 described herein. FIG. 2A shows a die 202 (e.g., a chip, a portionof a wafer, and/or the like) on which an emitter array has been formed.For example, and as described below, the emitter array may be an emitterarray with multiple groups of interspersed emitters. Notably, while someexample implementations described herein are described in the context ofan emitter array that emits light through an epitaxial side of the chip(top-emitting), the techniques and apparatuses described herein areapplicable to emitter arrays that emit light which travels through thesubstrate and out the opposite side of the die (bottom-emitting).

As shown in FIG. 2A, the emitter array includes various emitters 204(shown as black, white, and striped circles). For example, an emitter204 may include a laser, a vertical-cavity surface-emitting laser(VCSEL), a vertical external-cavity surface-emitting laser (VECSEL), alight-emitting diode (LED), an optical device, and/or the like. Emitters204 may each be included in one of multiple groups 205 of emitters 204.For example, the emitters 204 shown by black circles may be a firstgroup 205-1 of emitters 204, the emitters 204 shown by white circles maybe a second group 205-2 of emitters 204, and the emitters 204 shown bystriped circles may be a third group 205-3 of emitters 204. The variousgroups 205 of emitters 204 are described in more detail below.

As shown in FIG. 2A, die 202 may include multiple electrodes 206 (e.g.,shown as electrodes 206-1 through 206-3) to provide electrical power toemitters 204 of the emitter array on die 202. Additional electrodes maybe located on the opposite side of the die 202. Each electrode 206 maybe an anode or a cathode. Electrodes 206 may provide electricalconnection, respectively, to different groups 205-X (where X is theindex of a group of emitters 204) of emitters 204 of the emitter array.For example, electrode 206-1 may provide electrical connection to afirst group 205-1 of emitters 204, electrode 206-2 may provideelectrical connection to a second group 205-2 of emitters 204, andelectrode 206-3 may provide electrical connection to a third group 205-3of emitters 204. An electrode 206 may also provide electrical connectionto more than one group 205 of emitters 204 (e.g., as a common cathode ora shared electrode). An electrode 206 may provide electrical power (orcurrent) to a specific group 205-X of emitters 204 and not to othergroups 205-Y, 205-Z of emitters 204 (where Y and Z denote the index ofgroups other than X). For example, electrode 206-1 may provideelectrical power to the first group 205-1 of emitters 204 and may notprovide electrical power to other groups 205-1, 205-2 of emitters 204.

Different groups 205 of emitters 204 may be independently addressablefor independent lasing during operation. For example, a first group205-1 of emitters 204 may be independently addressable for lasingindependently from other groups 205-2, 205-3 of emitters 204 formed ondie 202 (e.g., the first group 205-1 of emitters 204 may be poweredand/or may lase independently from the second group 205-2 of emitters204 and the third group 205-3 of emitters 204, and/or the like).Independent addressability may be based on separate electricalconnections respectively between individual electrodes 206-1, 206-2,206-3 and specific groups 205-1, 205-2, 205-3 of emitters 204, asdescribed in more detail elsewhere herein.

As shown by reference number 208, emitters from different groups ofemitters 204 may be interspersed among each other. For example, anemitter 204 from a 205-1 group of emitters 204 may be adjacent to one ormore emitters from one or more other groups 205-2, 205-3 of emitters204. Continuing with the previous example, and referring to the specificemitters 204 shown by reference number 208, an emitter 204 from thefirst group 205-1 of emitters 204 (shown as the black circle withrespect to reference number 208) is adjacent to two emitters 204 fromthe second group 205-2 of emitters 204 (shown as the two white circlesadjacent to the black circle, one of which is shown in connection withreference number 208) and an emitter 204 from the third group 205-3 ofemitters 204 (shown as a striped circle adjacent to the black circle,also shown in connection with reference number 208).

A first minimum emitter-to-emitter distance (also referred to herein asa “global minimum emitter-to-emitter distance”) between two adjacentemitters 204 of the emitter array 205 may be less than a correspondingsecond minimum emitter-to-emitter distance (also referred to herein as a“minimum intra-group emitter-to-emitter distance”) between two emitters204 of the first group 205-1 of emitters 204, two emitters 204 of thesecond group 205-2 of emitters 204, or two emitters 204 of the thirdgroup 205-3 of emitters 204. For example, a first minimumemitter-to-emitter distance between the black emitter 204 (from thefirst group 205-1 of emitters 204) shown with respect to referencenumber 208 and a white emitter 204 (from the second group 205-2 ofemitters 204) or a striped emitter 204 (from the third group 205-3 ofemitters 204) may be less than a second minimum emitter-to-emitterdistance between two proximate black emitters 204 of the group 205-1 ofemitter array. In other words, a first a global minimumemitter-to-emitter distance of the set of emitters 205 between twoadjacent emitters 204 which may be of different 205-X, 205-Y groups ofemitters 204 may be less than a second minimum emitter-to-emitterdistance between two proximate emitters 204 of the same 205-X group ofemitters 204. As will be described below, two emitters 204 from a samegroup 205-X of emitters 204 may be proximate in the context of the samegroup of emitters 204 (e.g., a first emitter 204 is proximate to asecond emitter 204 in the context of a group 205-X of emitters 204 ifthe first emitter 204 and the second emitter 204 are in the same 205-Xgroup of emitters 204, and the first emitter 204 is the nearest neighborin that group to the second emitter 204, or vice versa, even though oneor more other emitters 204 included in one or more other groups 205-Y,205-Z of emitters 204 are between the first emitter 204 and the secondemitter 204). Y and Z denote the index of groups other than X.

A product of the global minimum emitter-to-emitter distance and a valueequal to at least a square root of 2 may be less than the minimumintra-group emitter-to-emitter-distance for a group of emitters 204. Inother words, the minimum intra-group emitter-to-emitter-distance may begreater than a square root of two times the global minimumemitter-to-emitter distance. In this way, emitters 204 in the set of allgroups 205 of emitters 204 may be spaced closer to each other than twoemitters 204 of a same group 205-X of emitters 204. Additionally, oralternatively, the difference in intra-group (e.g., within a group) andglobal minimum emitter-to-emitter distances facilitates increasedemitter size for a given area of die 202 (e.g., larger aperturediameter) relative to conventional emitter arrays, thereby facilitatingwider manufacturing tolerances for dies 202, and consequently lower chipcosts through a higher yield rate.

In operation, an emission pattern of emitters 204 of the emitter arrayis projected (and possibly repeated in multiple patterns) through opticsinto a scene. The scene may contain various surfaces and projecting thepatterns of dots is done to measure the 3D profile of these surfaces.The emission pattern of spots comes into focus on an image planesomewhere in the scene. Not all surfaces of interest will be locatedprecisely at the image plane, but may be near the image plane. At theimage plane, spots (i.e., images of the emitters 204) are their smallestand, at comparatively further distances from the image plane, will becomparatively larger in size (and also closer together). This variationin size and spacing permits assessment of depth of various surfaces inthe scene. However, at some distance from the image plane, the spots ofthe emission pattern will begin to merge into one another and individualdots will no longer be discernable and sensing of depth will not bepossible. Thus, there is a range along an axis perpendicular to theimage plane over which sensing depth is possible. This range is referredto herein as a sensor depth-of-field. A sch

The minimum emitter-to-emitter distance for a particular group, 205-X,of emitters 204 may be selected to avoid overlap of emission spots at aparticular depth of field (distance from the image plane) when lightfrom the emitters 204 of that group 205-X are projected into a scene.For example, by maintaining a minimum emitter-to-emitter spacing betweenthe closest emitters 204 from a particular group 205-X of emitters 204,the configuration of 205-X emitters 204 described herein may avoidoverlap between the proximate emitters 204 at a particular distance fromthe image plane (or depth-of-field) when only group 205-X is used toilluminate a scene at a particular time. An emitter-to-emitter distancemay refer to one or more of various manners of evaluating a distance (orspacing) between emitters 204. For example, an emitter-to-emitterdistance may be center-to-center spacing, a distance between opticalapertures of two emitters 204 (e.g., a center-to-center distance), adistance between oxide trenches of two emitters 204 (e.g., atrench-to-trench distance), and/or the like.

In FIG. 2A, the emitter array has a random pattern of emitters 204formed from the first group 205-1 of emitters 204, the second group205-2 of emitters 204, and the third group 205-3 of emitters 204. As aresult, the emitter array may emit a random pattern of spots when allthree groups of emitters 204 are lasing at the same time. Specificpatterns of the different groups of emitters 204 of the emitter arrayare described below in connection with FIGS. 2B-2D, and other patternsof emitters 204 of an emitter array are shown in and described belowwith respect to FIGS. 3 and 4.

FIG. 2B shows the first group 205-1 of emitters 204 of the emitter arrayof die 202 shown in FIG. 2A without showing the second group 205-2 ofemitters 204 (white circles from FIG. 2A) or the third group 205-3 ofemitters 204 (striped circles from FIG. 2A). As shown in FIG. 2B,emitters 204 of the first group 205-1 of emitters 204 are arranged in arandom pattern of emitters 204. A random pattern of emitters 204 is apattern of emitters 204 without a particular or discernable organizationor order (i.e., that is not able to be predicted) Reference number 210shows two adjacent emitters 204 of the first group 205-1 of emitters 204that are separated by a second minimum emitter-to-emitter distance(e.g., a minimum intra-group emitter-to-emitter distance) of the firstgroup 205-1 of emitters 204. As described elsewhere herein, this secondminimum emitter-to-emitter distance may be greater than a first minimumemitter-to-emitter distance between adjacent emitters 204 of differentgroups 205 of emitters 204 of the emitter array (e.g., any emitters 204in the emitter array). As a result, when light from only the first group205-1 of emitters 204 is projected into a scene, the distance from theimage plane where the emitters overlap (referred to here as thedepth-of-field) may be greater than the depth-of-field when light fromall emitters 204 is projected into a scene.

FIG. 2C shows the second group of emitters 204 of the emitter array ofdie 202 shown in FIG. 2A without showing the first group of emitters 204(black circles from FIG. 2A) or the third group of emitters 204 (stripedcircles from FIG. 2A). As shown in FIG. 2C, emitters 204 of the secondgroup of emitters 204 are arranged in a random pattern of emitters 204.Reference number 212 shows an example corresponding second minimumemitter-to-emitter distance between two adjacent emitters 204 of thesecond group of emitters 204. As described elsewhere herein, thiscorresponding second minimum emitter-to-emitter distance may be greaterthan a first minimum emitter-to-emitter distance between adjacentemitters 204 of different groups of emitters 204 of the emitter array.As a result, when lasing, the second group of emitters 204 may have adepth of field that is greater than an array that had emitters sized toavoid overlap when all emitters are lasing.

FIG. 2D shows the third group of emitters 204 of the emitter array ofdie 202 shown in FIG. 2A without showing the first group of emitters 204(black circles from FIG. 2A) or the second group of emitters 204 (whitecircles from FIG. 2A). As shown in FIG. 2D, emitters 204 of the thirdgroup of emitters 204 are arranged in a random pattern of emitters 204.Reference number 214 shows an example corresponding second minimumemitter-to-emitter distance between two adjacent emitters 204 of thethird group of emitters 204. As described elsewhere herein, thiscorresponding second minimum emitter-to-emitter distance may be greaterthan a first minimum emitter-to-emitter distance between adjacentemitters 204 of different groups of emitters 204 of the emitter array.As a result, when lasing, the third group of emitters 204 may have adepth of field that is greater than the depth of field when all emittersare lasing.

As described with regard to FIGS. 2B-2D, the first group of emitters204, the second group of emitters 204, and the third group of emitters204 may be each arranged in a random pattern of emitters. In addition,as described in connection with FIG. 2A, the emitter array overall mayhave a random pattern of emitters 204. In this way, the emitter arraymay have a random pattern of emitters formed from random patterns ofemitters corresponding to the first group of emitters 204, the secondgroup of emitters 204, and the third group of emitters 204. In addition,as shown in FIGS. 2B-2D, the different groups of emitters 204 thatcomprise the emitter array may have different random patterns ofemitters 204. This reduces or eliminates sensing issues that wouldotherwise occur from the different groups of emitters 204 having a samepattern of emitters 204 if the groups were lasing at the same time.

In this way, some implementations described herein provide a die 202that includes multiple groups of emitters 204 and electrodes 206 toprovide electrical connections to to the multiple groups of emitters204. For example, the electrodes 206 may be configured to independentlyelectrically power the corresponding groups of emitters 204. Inaddition, a first minimum emitter-to-emitter distance between twoadjacent emitters (e.g., adjacent emitters 204 that are included indifferent groups of emitters 204) of an emitter array formed from themultiple groups of emitters 204 may be less than a second minimumemitter-to-emitter distance between two emitters of a group of emitters204. For example, a product of the first minimum emitter-to-emitterdistance and a square root of two may be less than the second minimumemitter-to-emitter distance. This configuration of die 202 facilitatescloser packing of larger emitters 204 on die 202 while reducing oreliminating overlap of emission spots at a depth of field relative toconventional emitter arrays. For example, the first minimumemitter-to-emitter distance may facilitate closer packing of emitters204. In addition, independent and separate lasing of different groups ofemitters 204 in combination with the corresponding second minimumemitter-to-emitter distance may reduce or eliminate overlap of emissionspots at a depth of field. Reducing or eliminating overlap of emissionspots at a depth of field may increase a depth of field of an emitterarray (e.g., by increasing an image depth at which emission spots of theemitter array begin to overlap) relative to conventional emitter arrays.In addition, reducing or eliminating overlap of emission spots at adepth of field may improve optical resolution at the depth of field.

As indicated above, FIGS. 2A-2D are provided merely as one or moreexamples. Other examples may differ from what is described with regardto FIGS. 2A-2D. For example, although three different groups of emitters204 were shown in, and described with respect to, FIGS. 2A-2D, otherexample implementations may have different quantities of groups ofemitters 204.

FIG. 3 is a diagram depicting an example implementation 300 describedherein. FIG. 3 shows an example configuration of an emitter array on adie 202, similar to that described elsewhere herein. For example, theemitter array may include multiple groups of emitters 204 interspersedwith each other and electrodes 206 to provide electrical connections tothe multiple groups of emitters 204, similar to that described elsewhereherein. The irregular pattern of emitters 204 within each group may behelpful to locate the pattern when multiple copies of a particular groupof emitters 204 is projected into a scene. Typically, 3D sensing withstructured-light cannot use uniform patterns of spots.

As shown by reference number 310, the emitter array may include, forexample, three groups of emitters 204. For example, the three groups ofemitters 204 may include a first group of emitters 204 shown by theblack circles, a second group of emitters 204 shown by the whitecircles, and a third group of emitters 204 shown by the striped/shadedcircles. As further shown in FIG. 3, the multiple groups of emitters 204may be arranged in corresponding non-random patterns. A non-randompattern of emitters 204 is a pattern of emitters with a particularorganization or order. For example, a non-random pattern may include agrid pattern, a hexagonal pattern, a known curve pattern, a parabolicpattern, and/or another type of organized or ordered pattern formed fromemitters 204. For example, and with respect to the first group of(black) emitters 204, emitters 204 of the first group of emitters 204may be arranged in a two-dimensional pattern of columns (shown byreference number 320) and rows (shown by reference number 330).

As further shown in FIG. 3, in some implementations, the first group ofemitters 204 may have irregular spacing between emitters 204 of thefirst group of emitters 204. That is, emitter-to-emitter distancesbetween pairs emitters 204 in the first group of emitters 204 may differamong pairs of emitters 204 in the first group of emitters 204. Forexample, a spacing between a first emitter 204, included in the firstgroup of emitters 204. and a second emitter 204, included in the firstgroup of emitters 204, that is proximate to the first emitter 204 may bedifferent than a spacing between the first emitter 204 and a thirdemitter 204, included in the first group of emitters 204, that isproximate to the first emitter 204. The second group of emitters 204 andthe third group of emitters 204 may be arranged in a manner similar tothat described with regard to the first group of emitters 204. In someimplementations, a group of emitters 204 may have regular spacingbetween emitters 204 of the group of emitters 204. That is,emitter-to-emitter distances between pairs emitters 204 in the firstgroup of emitters 204 may be the same among pairs of emitters 204 in thegroup of emitters 204.

As shown by reference number 340, the emitter array on die 202 may havea non-random pattern of emitters 204 formed from the multiple groups ofemitters 204. For example, the emitter array may have a non-randomtwo-dimensional pattern of emitters 204, where emitters 204 of theemitter array are formed in rows and columns of emitters 204. Inaddition, similar to the multiple groups of emitters 204, emitters 204of the emitter array may have an irregular spacing between emitters 204of the emitter array.

As indicated above, FIG. 3 is provided merely as one or more examples.Other examples may differ from what is described with regard to FIG. 3.

FIG. 4 is a diagram depicting an example implementation 400 describedherein. FIG. 4 shows an example configuration of an emitter array on die202, similar to that described elsewhere herein. For example, theemitter array may include multiple groups of emitters 204 interspersedwith each other and electrodes 206 corresponding to the multiple groupsof emitters 204, similar to that described elsewhere herein. Inaddition, FIG. 4 shows a manner in which a uniform, non-random patternof emitters 204 for an emitter array can be formed from multiple groupsof emitters 204 that have corresponding non-uniform patterns of emitters204.

Reference number 410 shows an emitter array that includes two groups ofemitters 204. The two groups of emitters 204 are shown by the blackcircles and the white circles. As shown by reference number 420, theemitters 204 may be in a non-random pattern of alternating emitters 204(e.g., on a per-row and a per-column basis).

Reference number 430 shows an emitter array that includes three groupsof emitters 204, where the three groups of emitters 204 havecorresponding non-uniform patterns of emitters 204. A non-uniformpattern of emitters 204 is a pattern of emitters 204 selected from anon-random pattern of emitters 204 such that the selected emitters haveno discernable pattern, as described below. As shown by reference number440, to form the emitter array that has a non-random pattern of emitters204 formed from multiple groups of emitters 204 that have correspondingnon-uniform patterns of emitters 204, a third group of emitters 204(shown by the striped circles) may be selected from the first group ofemitters 204 and/or the second group of emitters 204 described withrespect to the emitter array shown by reference number 410.

As further shown by reference number 440, emitters 204 selected for thethird group of emitters 204 may form a non-uniform pattern of emitters204. For example, the selected emitters 204 may not form a randompattern based on having been selected from the non-random pattern ofemitters 204, and may have no discernable pattern (e.g., such thatselected emitters 204 do not form rows and columns that include similarquantities of emitters 204, do not form a pattern that has a particularshape, and/or the like)). As such, the first group of emitters 204 andthe second group of emitters 204 may additionally have correspondingnon-uniform patterns of emitters 204 after selection of the third groupof emitters 204. Based on including three non-uniform patterned emitters204, the emitter array shown with respect to reference number 420 mayhave sufficient variability in patterns of the emitters 204 between thedifferent groups of emitters 204 to reduce or eliminate sensing issuesthat may occur with the emitter array shown with respect to referencenumber 410 due to that emitter array including two groups of emitters204 that have similar patterns of emitters 204 (e.g., a perfectlyuniform pattern, when repeated, may be difficult to locate, whereas anon-uniform pattern may be easier to locate). In some cases, includingone or more additional groups of emitters 204 in the emitter array shownwith respect to reference number 420 may further reduce or eliminatesensing issues.

A quantity and/or location of emitters 204 selected for inclusion in thethird group of emitters 204 may depend on emitter-to-emitter distancesof inter-group and intra-group emitters 204 before and after selectionof the emitters 204 for the third group of emitters 204. For example, athreshold quantity of emitters 204 may need to be selected such that afirst minimum emitter-to-emitter distance between two adjacent emitters204 of the emitter array is greater than a second minimumemitter-to-emitter distance between two adjacent emitters 204 of any oneof the groups of emitters 204, similar to that described elsewhereherein. In the examples shown in FIG. 4, groups of emitters 204 beingchosen from among diagonal emitters 204 of entire set of emitters 204 inthe emitter array means a minimum emitter-to-emitter distance betweenemitters 204 in a given group of emitters is a √2 equal or greater thana minimum emitter-to-emitter distance among emitters in the entire setof emitters 204 of the emitter array. It is apparent this relation istrue when considering the center-to-center to distance betweenneighboring emitters because the length along the diagonal betweenneighboring emitter centers is √2 longer than the horizontal or verticalcenter to center spacing. When considering the distance (gap) betweenemitters (e.g., which equals the center-to-center spacing less theemitter diameter), the ratio becomes larger than √2 because eachdistance is smaller by a fixed amount.

As indicated above, FIG. 4 is provide merely as an example. Otherexamples may differ from what is described with regard to FIG. 4.

Notably, while particular examples of intra-group patterns and overallemitter array patterns are shown and described in FIGS. 2A-2D, 3, and 4,other examples are possible. For example, emitters 204 of an emitterarray may form a non-random pattern of emitters 204 with irregularemitter-to-emitter spacing (e.g., a parabolic grid), a non-randompattern of emitters 204 with regular emitter-to-emitter spacing, arandom pattern with regular emitter-to-emitter spacing, and/or the like.In general, emitters 204 of a given emitter array may have anycombination of pattern and spacing described herein.

FIG. 5 is a flow chart of an example process 500 for forming an emitterarray with multiple groups of interspersed emitters 204. For example,FIG. 5 shows an example process 500 for manufacturing an emitter arrayon die 202 as described above.

As shown in FIG. 5, process 500 may include providing a substrate onwhich an emitter array is to be formed (block 510). For example, process500 may include providing a die (e.g., die 202) on which an emitterarray (e.g., a laser array) is to be formed. The substrate may include agallium arsenide (GaAs) substrate and/or the like. The substrate may beseparated from a wafer (e.g., a GaAs wafer) prior to forming the emitterarray on the substrate.

As further shown in FIG. 5, process 500 may include forming, afterproviding the substrate, a first plurality of emitters of the emitterarray, a second plurality of emitters of the emitter array, and a thirdplurality of emitters of the emitter array on or within the substrate(block 520). For example, process 500 may include forming a firstplurality of emitters (e.g., a first group of emitters 204), a secondplurality of emitters (e.g., a second group of emitters 204), and athird plurality of emitters (e.g., a third group of emitters 204) on orwithin the substrate after providing the substrate. To form a pluralityof emitters, various epitaxial layers may be formed on the substrate.The plurality of emitters may be formed in a pattern, such as atwo-dimensional pattern (e.g., a grid pattern, a hexagonal pattern, arandom pattern, a non-uniform pattern, and/or the like).

In some implementations, the first plurality of emitters, the secondplurality of emitters, and the third plurality of emitters may be formedsuch that emitters of the first plurality of emitters are interspersedamong the second plurality of emitters, emitters of the second pluralityof emitters are interspersed among the third plurality of emitters, andemitters of the third plurality of emitters are interspersed among thefirst plurality of emitters. For example, an emitter from the firstplurality of emitters may be adjacent to one or more emitters from thesecond plurality of emitters and the third plurality of emitters, andlikewise for the second plurality of emitters and the third plurality ofemitters.

In some implementations, the first plurality of emitters, the secondplurality of emitters, and the third plurality of emitters may be formedsuch that a first minimum emitter-to-emitter distance between any twoadjacent emitters of the emitter array is less than a correspondingsecond minimum emitter-to-emitter distance between two of the firstplurality of emitters, two of the second plurality of emitters, or twoof the third plurality of emitters. For example, a first minimumemitter-to-emitter distance between any two adjacent emitters of theemitter array may be less than a second minimum emitter-to-emitterdistance between two emitters for any of the first plurality ofemitters, the second plurality of emitters, and the third plurality ofemitters. As a specific example, a product of the first minimumemitter-to-emitter distance and a value equal to at least a square rootof two may be less than the second minimum emitter-to-emitter distance.

In some implementations, the first plurality of emitters, the secondplurality of emitters, and the third plurality of emitters may be formedsuch that the first plurality of emitters, the second plurality ofemitters, and the third plurality of emitters are electrically isolatedfrom each other for independent lasing. For example, a plurality ofemitters may be associated with a metallization layer (e.g., a goldmetallization layer, a silver metallization layer, a coppermetallization layer, and/or the like) that is electrically isolated fromother metallization layers corresponding to other pluralities ofemitters. In addition, the emitter array may be associated withelectrodes (e.g., electrodes 206) that provide electrical connections tothe first plurality of emitters, the second plurality of emitters, andthe third plurality of emitters, and the electrodes may provideelectrical power to the corresponding pluralities of emittersindependently.

In some implementations, the first plurality of emitters, the secondplurality of emitters, and the third plurality of emitters may be formedin corresponding patterns, and the resulting emitter array may have apattern of emitters formed from the corresponding patterns. For example,the first plurality of emitters, the second plurality of emitters, andthe third plurality of emitters may be formed in a random pattern ofemitters such that the emitter array has a random pattern of emitters,similar to that described with respect to FIGS. 2A-2D. Additionally, oralternatively, and as another example, the first plurality of emitters,the second plurality of emitters, and the third plurality of emittersmay be formed in a non-random pattern of emitters such that the emitterarray has a non-random pattern of emitters with an irregular spacingbetween emitters of the emitter array, similar to that described withrespect to FIG. 3. Additionally, or alternatively, and as anotherexample, the first plurality of emitters, the second plurality ofemitters, and the third plurality of emitters may be formed in anon-uniform pattern of emitters such that the emitter array has anon-random pattern of emitters, similar to that described with regard toFIG. 4.

As further shown in FIG. 5, process 500 may include electricallyconnecting the first plurality of emitters, the second plurality ofemitters, and the third plurality of emitters to correspondingelectrodes (block 530). For example, process 500 may includeelectrically connecting the first plurality of emitters, the secondplurality of emitters, and the third plurality of emitters tocorresponding electrodes after forming the first plurality of emitters,the second plurality of emitters, and the third plurality of emitters.Electrically connecting the first plurality of emitters, the secondplurality of emitters, and the third plurality of emitters to thecorresponding electrodes may include forming metallization layerscorresponding to the first plurality of emitters, the second pluralityof emitters, and the third plurality of emitters on the emitter array toelectrically connect the first plurality of emitters, the secondplurality of emitters, and the third plurality of emitters to thecorresponding anodes. For example, the metallization layers may beelectrically isolated from each other to facilitate independent poweringand/or lasing of different pluralities of emitters.

In some implementations, forming the first plurality of emitters, thesecond plurality of emitters, and the third plurality of emitters mayinclude forming each of the first plurality of emitters, the secondplurality of emitters, and the third plurality of emitters such that theemitter array has a random pattern of emitters.

In some implementations, forming the first plurality of emitters, thesecond plurality of emitters, and the third plurality of emitters mayinclude forming each of the first plurality of emitters, the secondplurality of emitters, and the third plurality of emitters in anon-random pattern such that the emitter array has a non-random patternof emitters with an irregular spacing between emitters.

In some implementations, forming the first plurality of emitters, thesecond plurality of emitters, and the third plurality of emitters mayinclude forming each of the first plurality of emitters, secondplurality of emitters, and the third plurality of emitters in anon-uniform pattern of emitters such that the emitter array has anon-random pattern of emitters.

In some implementations, forming the first plurality of emitters, thesecond plurality of emitters, and the third plurality of emitters mayinclude forming the first plurality of emitters, the second plurality ofemitters, and the third plurality of emitters such that a product of thefirst minimum emitter-to-emitter distance and a value equal to at leasta square root of two is less than the second minimum emitter-to-emitterdistance.

Although FIG. 5 shows example blocks of process 500, in someimplementations, process 500 may include additional blocks, fewerblocks, different blocks, or differently arranged blocks than thosedepicted in FIG. 5. Additionally, or alternatively, two or more of theblocks of process 500 may be performed in parallel.

The foregoing disclosure provides illustration and description, but isnot intended to be exhaustive or to limit the implementations to theprecise forms disclosed. Modifications and variations may be made inlight of the above disclosure or may be acquired from practice of theimplementations.

As used herein the term “layer” is intended to be broadly construed asone or more layers and includes layers oriented horizontally,vertically, or at other angles.

Some implementations are described herein in connection with thresholds.As used herein, satisfying a threshold may, depending on the context,refer to a value being greater than the threshold, more than thethreshold, higher than the threshold, greater than or equal to thethreshold, less than the threshold, fewer than the threshold, lower thanthe threshold, less than or equal to the threshold, equal to thethreshold, or the like.

Even though particular combinations of features are recited in theclaims and/or disclosed in the specification, these combinations are notintended to limit the disclosure of various implementations. In fact,many of these features may be combined in ways not specifically recitedin the claims and/or disclosed in the specification. Although eachdependent claim listed below may directly depend on only one claim, thedisclosure of various implementations includes each dependent claim incombination with every other claim in the claim set.

No element, act, or instruction used herein should be construed ascritical or essential unless explicitly described as such. Also, as usedherein, the articles “a” and “an” are intended to include one or moreitems, and may be used interchangeably with “one or more.” Further, asused herein, the article “the” is intended to include one or more itemsreferenced in connection with the article “the” and may be usedinterchangeably with “the one or more.” Furthermore, as used herein, theterm “set” is intended to include one or more items (e.g., relateditems, unrelated items, a combination of related and unrelated items,etc.), and may be used interchangeably with “one or more.” Where onlyone item is intended, the phrase “only one” or similar language is used.Also, as used herein, the terms “has,” “have,” “having,” or the like areintended to be open-ended terms. Further, the phrase “based on” isintended to mean “based, at least in part, on” unless explicitly statedotherwise. Also, as used herein, the term “or” is intended to beinclusive when used in a series and may be used interchangeably with“and/or,” unless explicitly stated otherwise (e.g., if used incombination with “either” or “only one of”).

What is claimed is:
 1. An optical device comprising: an emitter arrayconsisting of a plurality of emitter groups, each emitter group beingindependently addressable from other emitter groups, of the plurality ofemitter groups, for independently lasing, and emitters of the pluralityof emitter groups being interspersed within the emitter array such that:a minimum emitter-to-emitter distance within the emitter array is lessthan a minimum emitter-to-emitter distance within any of the pluralityof emitter groups, and no two emitters, of a same group of the pluralityof emitter groups, are nearest neighbors.
 2. The optical device of claim1, wherein a product of the minimum emitter-to-emitter distance withinthe emitter array and a value equal to at least a square root of two isless than the minimum emitter-to-emitter distance within any of theplurality of emitter groups.
 3. The optical device of claim 1, whereinthe minimum emitter-to-emitter distance within any of the plurality ofemitter groups is selected to avoid overlap of emission spots at aparticular depth of field when lasing only one of the plurality ofemitter groups.
 4. The optical device of claim 1, further comprising: aplurality of electrodes, each providing an electrical connection to arespective one of the plurality of emitter groups, wherein each of theplurality of electrodes is configured to provide electrical power to arespective one of the plurality of emitter groups and independently fromother electrodes of the plurality of electrodes.
 5. The optical deviceof claim 1, wherein an emitter group, of the plurality of emittergroups, has at least one of a non-random pattern within the emitterarray or irregular spacing among emitters of the emitter group.
 6. Theoptical device of claim 1, wherein the emitter array has a non-randompattern of emitters formed from the plurality of emitter groups.
 7. Anoptical device, comprising: an emitter array consisting of a pluralityof emitter groups, wherein emitters of the plurality of emitter groupsare interspersed within the emitter array such that; a minimumemitter-to-emitter distance within the emitter array is less than aminimum emitter-to-emitter distance within any of the plurality ofemitter groups, and no two emitters, of a same group of the plurality ofemitter groups, are nearest neighbors, and wherein each emitter group ofthe plurality of emitter groups is independently addressable forindependent lasing; and a plurality of electrodes that each provide anelectrical connection to a respective one of the plurality of emittergroups.
 8. The optical device of claim 7, wherein a product of theminimum emitter-to-emitter distance within the emitter array and a valueequal to at least a square root of two is less than the minimumemitter-to-emitter distance within any of the plurality of emittergroups.
 9. The optical device of claim 7, wherein the minimumemitter-to-emitter distance within any of the plurality of emittergroups is selected to avoid overlap of emission spots at a particulardepth of field when lasing only one of the plurality of emitter groups.10. The optical device of claim 7, wherein the plurality of electrodesare configured to provide electrical power to each of the plurality ofemitter groups, respectively and independently from each other.
 11. Theoptical device of claim 7, wherein each of the plurality of emittergroups has a non-random pattern within the emitter array.
 12. Theoptical device of claim 7, wherein the emitter array has a non-randompattern of emitters with an irregular spacing between emitters of theemitter array.
 13. The optical device of claim 7, wherein each of theplurality of emitter groups has a non-uniform pattern of emitters, andwherein the emitter array has a non-random pattern of emitters formedfrom the plurality of emitter groups.
 14. A vertical cavity surfaceemitting laser (VCSEL) array, consisting of: a plurality of groups ofVCSELs, wherein VCSELs of the plurality of VCSELs are interspersedwithin the VCSEL array, wherein no two VCSELs, of a same group of theplurality of groups of VCSELs, are nearest neighbors, wherein a minimumemitter-to-emitter distance within the VCSEL array is less than aminimum emitter-to-emitter distance within any of the plurality ofgroups of VCSELs, and wherein the VCSEL array is configured such thatthe plurality of groups of VCSELs are capable of lasing independently ofeach other.
 15. The VCSEL array of claim 14, wherein a product of theminimum emitter-to-emitter distance within the VCSEL array and a valueequal to at least a square root of two is less than the minimumemitter-to-emitter distance within any of the plurality of groups ofVCSELs.
 16. The VCSEL array of claim 14, wherein the plurality of groupsof VCSELs are capable of lasing at different times.
 17. The VCSEL arrayof claim 14, further comprising: electrodes providing electricalconnections to the plurality of groups of VCSELs, wherein the electrodesare configured to provide electrical power independently from eachother.
 18. The VCSEL array of claim 14, wherein patterns of VCSELscorresponding to the plurality of groups of VCSELs are different than apattern of VCSELs for the VCSEL array.
 19. The VCSEL array of claim 18,wherein the patterns of VCSELs are non-uniform patterns of VCSELs andthe pattern of VCSEL is a non-random pattern of VCSELs.
 20. The VCSELarray of claim 14, wherein the minimum emitter-to-emitter distancewithin any of the plurality of groups of VCSELs is selected to avoidoverlap of emission spots of VCSELs at a particular depth of field whenlasing only one of the plurality of groups of VCSELs.